From patchwork Thu May 30 13:45:42 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Frederic Weisbecker X-Patchwork-Id: 13680433 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5C8FC17D89C; Thu, 30 May 2024 13:46:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717076764; cv=none; b=bT2UwxTI63fLef9KXcPaRW/e34ZykJ6ZZyyGaQ2ApFCh801N/0L3mUNEvJ/bQhv9ayq9u9pNLHiD/woqakaI+0pT8T+Fmkuo0xqrHu+I5EyPb3XBeET9i1juIsbFKmTVfS1KZQu1ewd0bNxLETHUC0J2hRAE+XVrDeMONUt7ZDU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717076764; c=relaxed/simple; bh=QUqTf47U5266+G1RAYGGur6TId4oP4I8Z4uT9fa4U8Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=lmxe9od22Nyv0fvXneEypbDNNBIucseEsUUnlflS5LEfupu2s+uxj0EhFRUVc3wQwFlzOImANQFjIwbCLG0F67F1vZR7MP0XMvBbRGEMhKTpyuz50EkK75ahmMcXf6RQN/d498WjqLhvsigf56PUGW1EwXh47HADeMGTW/SBltU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RV6lIgdq; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RV6lIgdq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5A1D6C32786; Thu, 30 May 2024 13:46:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1717076763; bh=QUqTf47U5266+G1RAYGGur6TId4oP4I8Z4uT9fa4U8Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RV6lIgdqok+I3N32iQOTjFIewW7ShzbN5c8IEDw/xUl3IqeA7neBXsufFpkIleUht PA2oWdhohOGwViCjISPag8qAV5T+9yug+yumsdqh5Q8RRt2/FoBwllY7ovT14dObSy llfrTtfuncXmPPJp7jtGzVb+TuCcHg9T9z5XO08whx281ciU/Ia3c57Y9xyUHp1LRy 3ol14uzlG1ST66rKawwHQiRNtHVMzls9Iufrhwc/0tdqJFnlGp7/LvUoB9EIQiRVA8 CUtu95MQzYqDTCwwWk3Y3KonzRbvi5MubD6rLwyMTFszdIu6Dzq2FN/RekwOL9kPIE cniS3ZZGrABUg== From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Boqun Feng , Joel Fernandes , Neeraj Upadhyay , "Paul E . McKenney" , Uladzislau Rezki , Zqiang , rcu Subject: [PATCH 01/11] rcu/nocb: Introduce RCU_NOCB_LOCKDEP_WARN() Date: Thu, 30 May 2024 15:45:42 +0200 Message-ID: <20240530134552.5467-2-frederic@kernel.org> X-Mailer: git-send-email 2.45.1 In-Reply-To: <20240530134552.5467-1-frederic@kernel.org> References: <20240530134552.5467-1-frederic@kernel.org> Precedence: bulk X-Mailing-List: rcu@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Checking for races against concurrent (de-)offloading implies the creation of !CONFIG_RCU_NOCB_CPU stubs to check if each relevant lock is held. For now this only implies the nocb_lock but more are to be expected. Create instead a NOCB specific version of RCU_LOCKDEP_WARN() to avoid the proliferation of stubs. Signed-off-by: Frederic Weisbecker --- include/linux/rcupdate.h | 7 +++++++ kernel/rcu/tree_nocb.h | 14 -------------- kernel/rcu/tree_plugin.h | 4 ++-- 3 files changed, 9 insertions(+), 16 deletions(-) diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index be450a3477be..9161e00a0cf4 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -145,11 +145,18 @@ void rcu_init_nohz(void); int rcu_nocb_cpu_offload(int cpu); int rcu_nocb_cpu_deoffload(int cpu); void rcu_nocb_flush_deferred_wakeup(void); + +#define RCU_NOCB_LOCKDEP_WARN(c, s) RCU_LOCKDEP_WARN(c, s) + #else /* #ifdef CONFIG_RCU_NOCB_CPU */ + static inline void rcu_init_nohz(void) { } static inline int rcu_nocb_cpu_offload(int cpu) { return -EINVAL; } static inline int rcu_nocb_cpu_deoffload(int cpu) { return 0; } static inline void rcu_nocb_flush_deferred_wakeup(void) { } + +#define RCU_NOCB_LOCKDEP_WARN(c, s) + #endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */ /* diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h index 3ce30841119a..f4112fc663a7 100644 --- a/kernel/rcu/tree_nocb.h +++ b/kernel/rcu/tree_nocb.h @@ -16,10 +16,6 @@ #ifdef CONFIG_RCU_NOCB_CPU static cpumask_var_t rcu_nocb_mask; /* CPUs to have callbacks offloaded. */ static bool __read_mostly rcu_nocb_poll; /* Offload kthread are to poll. */ -static inline int rcu_lockdep_is_held_nocb(struct rcu_data *rdp) -{ - return lockdep_is_held(&rdp->nocb_lock); -} static inline bool rcu_current_is_nocb_kthread(struct rcu_data *rdp) { @@ -1653,16 +1649,6 @@ static void show_rcu_nocb_state(struct rcu_data *rdp) #else /* #ifdef CONFIG_RCU_NOCB_CPU */ -static inline int rcu_lockdep_is_held_nocb(struct rcu_data *rdp) -{ - return 0; -} - -static inline bool rcu_current_is_nocb_kthread(struct rcu_data *rdp) -{ - return false; -} - /* No ->nocb_lock to acquire. */ static void rcu_nocb_lock(struct rcu_data *rdp) { diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 51125f4130fd..0d6b152a9a17 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -24,10 +24,10 @@ static bool rcu_rdp_is_offloaded(struct rcu_data *rdp) * timers have their own means of synchronization against the * offloaded state updaters. */ - RCU_LOCKDEP_WARN( + RCU_NOCB_LOCKDEP_WARN( !(lockdep_is_held(&rcu_state.barrier_mutex) || (IS_ENABLED(CONFIG_HOTPLUG_CPU) && lockdep_is_cpus_held()) || - rcu_lockdep_is_held_nocb(rdp) || + lockdep_is_held(&rdp->nocb_lock) || (!(IS_ENABLED(CONFIG_PREEMPT_COUNT) && preemptible()) && rdp == this_cpu_ptr(&rcu_data)) || rcu_current_is_nocb_kthread(rdp)),